<!DOCTYPE html>

<html>
    <head>
        <meta charset="utf-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <title>Css Calculator by Aryan Kapoor</title>
        <meta name="description" content="a css calculator">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        
    </head>
    
    <style>
        body 
{
display: flex;
justify-content: center;
align-items: center;
min-height: 100vh;
background: #574b90;
}

span {
border-radius: 8px;
}



.calculator 
{
position: relative;
display: grid;
}

.calculator .value
{
grid-column: span 4;
height: 100px;
text-align: right;
border: none;
outline: none;
padding: 10px;
font-size: 18px;
}

.calculator span
{
display: grid;
width: 60px;
height: 60px;
color: #fff;
background: #0c2835;
place-items: center;
border: 1px solid rgba(0,0,0,.1);
}

.calculator span:active 
{
background: #74ff3b;
color: #111;
}

.calculator span.clear
{
grid-column: span 2;
width: 120px;
background: #ff3077;
}

.calculator span.plus
{
grid-row: span 2;
height: 120px;
}

.calculator span.equal
{
background: #03b1ff;
}
</style>
    <body>

        <form class="calculator" name="calc">
            <input type="text" name="txt" class="value" readonly="">
            
            <span class="num clear" onclick="document.calc.txt.value =''">c</span>
            <span class="num" onclick="document.calc.txt.value +='/'">/</span>
            <span class="num" onclick="document.calc.txt.value +='*'">*</span>
            <span class="num" onclick="document.calc.txt.value +='7'">7</span>
            <span class="num" onclick="document.calc.txt.value +='8'">8</span>
            <span class="num" onclick="document.calc.txt.value +='9'">9</span>
            <span class="num" onclick="document.calc.txt.value +='-'">-</span>
            <span class="num" onclick="document.calc.txt.value +='4'">4</span>
            <span class="num" onclick="document.calc.txt.value +='5'">5</span>   <span class="num" onclick="document.calc.txt.value +='6'">6</span>   <span class="num plus" onclick="document.calc.txt.value +='+'">+</span>   <span class="num" onclick="document.calc.txt.value +='3'">3</span>   <span class="num" onclick="document.calc.txt.value +='2'">2</span>   <span class="num" onclick="document.calc.txt.value +='1'">1</span>   <span class="num" onclick="document.calc.txt.value +='0'">0</span> 
            <span class="num" onclick="document.calc.txt.value +='00'">00</span><span class="num" onclick="document.calc.txt.value +='.'">.</span>
            <span class="num equal" onclick="document.calc.txt.value = eval(calc.txt.value)">=</span>
          </form>  
           
        
        
    </body>
</html>
